It is known in apparatuses of the above kind to provide the housing with a rotating nozzle assembly, in which the nozzle rotation is produced by a moving means in the form of a hydraulic motor comprising a small turbine driven by the cleaning liquid flowing to the nozzle assembly. An apparatus of this type does not work completely satisfactorily, there being no compensation for the wear caused by the rotation of the nozzle assembly.
An apparatus is furthermore known, in which the nozzle assembly is tiltably mounted on an shaft projecting from the housing, and in which the tilting movement is produced by a hydraulic motor within the housing. In this case the wear occurs around the shaft seal between shaft and housing, while the nozzle assembly performs its tilting movement. The shaft seal will consequently be the weak point.
The known constructions have in common that they are not as reliable as required, as they are not self-compensating with regard to the wear caused by the movement of the nozzle assembly. They are furthermore not easily assembled.